Devices to aid in the flossing of teeth are well known. Despite the large number of patents disclosing such devices, they have met with little commercial success, and the primary flossing technique still consists of tensioning a length of floss between the user's hands. An acceptable flossing device must possess a number of attributes, some of the more important being ease of use, ability to thoroughly clean the device, ease of construction, and modest cost. All of the prior art devices known to applicants are deficient in one or more of the foregoing respects, and it is perhaps for this reason that they have not achieved commercial success.
The prior art discloses many flossing devices wherein a spool of floss is supported on the device, the free end of the floss being tensioned across a pair of prongs at one end of the device, the prongs being spaced such that the length of floss therebetween may be inserted between the teeth for effecting cleaning.
A principal drawback of one such device disclosed in U.S. Pat. No. 3,886,956, is the requirement that tension be effected by having the user pull on the free end of the floss during cleaning. Inasmuch as the user must grasp the device with one hand, tensioning must be effected with the other hand, and this device therefore offers little or no advantage over the usual technique of simply stretching the length of floss between the hands.
In other prior art flossing devices of the type of interest here, the floss is tensioned by securing the free end in some fashion to the body of the device. While these flossing devices are advantageous in that the flossing operation may be accomplished with one hand, the known devices have a variety of drawbacks. For example, in U.S. Pat. No. 3,939,853, a button is secured to the device behind the prongs, and tensioning is effected by wrapping the floss about the small space between the button and the body of the device. However, inasmuch as it is necessary to advance a clean length of floss into the space between the prongs after one or at most a few cleaning operations, this arrangement is disadvantageous as the technique for advancing the floss, comprising unwinding the floss from around the button, pulling on the floss, and then rewinding the floss on the button, is cumbersome and time consuming.
A similar drawback is evident in still other flossing devices of the type of interest here. Thus, in the devices disclosed in U.S. Pat. Nos. 2,837,098 and 3,814,114, tensioning of the floss is effected by an axially moveable or rotatable member which traps the free end of the floss, and also the length of floss extending from the spool to the prongs, in a passage formed in the body of the device. In these devices, advancement of the floss for exposing a clean length of floss between the prongs requires grasping the device with one hand, moving the tensioning means, pulling on the floss to advance it, and then again moving the tensioning means to retension the floss. Inasmuch as the tensioning means in these devices cannot be manipulated by the same hand being used to hold the flossing device, it will be apparent that floss advancement is cumbersome and requires a certain amount of dexterity.
In the devices disclosed in FIGS. 4-6 of U.S. Pat. No. 3,924,647, the free end of the floss passes through a hole in the body and is tensioned by a plug or the like disposed in the hole and moveable between a position wherein the floss is trapped between the plug and the defining walls of the passage, and another position wherein the strand is freed for pulling on the free end thereof for advancing the floss. Because the free end of the floss comprises floss which has been previously used in a cleaning operation and is thereby soiled, the passage through which the free end passes also eventually becomes soiled. As this passage extends through the device, it will be apparent that cleaning of the passage is quite difficult, unless a specially shaped implement designed to fit in the passage is used. This is also true of the devices mentioned in U.S. Pat. Nos. 2,837,098 and 3,814,114 discussed above.
U.S. Pat. No. 3,847,168 discloses a device similar to that disclosed in U.S. Pat. No. 3,886,956, excepting that the free end of the floss does not pass through the same passage as the plug, but rather is trapped between an enlarged head of the plug and the confronting surface of the body of the flossing device. Again, however, it will be apparent that the space between the enlarged plug head and the body of the device will inevitably become soiled, and because the clearance in this space is quite small, thorough cleaning of this device is also difficult. In addition, in this device the free end of the floss is not inherently retained in position under the enlarged head of the plug when the plug is moved to the position wherein the floss is freed for advancement. Consequently, this device also suffers the drawback of cumbersome operation as the user is required to manually position the floss under the plug head after each advancement.
It is therefore an object of the present invention to provide a flossing device which requires a minimal amount of dexterity to use, and which may be readily and easily cleaned.
It is a further object of the present invention to provide a flossing device wherein the body of the device is shaped to maximize the efficiency and simplicity of the flossing operation.